title: Targeting interleukin-21 in inflammatory diseases.
abstract: BACKGROUND
  IL-21, a new member of the type 1 cytokine superfamily, is produced by various subsets of CD4(+) T cells and binds to a composite receptor that consists of a specific receptor, termed IL-21 receptor and the common γ-chain subunit. Initially considered to be a critical regulator of T and B cell function, IL-21 is now known to regulate the activity of many other cell types, including both immune and non-immune cells.
  
  
  METHODS
  In this review, we discuss the biological features of IL-21 and summarize recent advances in the pathogenic role of IL-21 in chronic inflammatory diseases. Moreover, we discuss why IL-21 blockers can have a place in the therapeutic armamentarium for patients with immune-mediated diseases and the potential risks of such treatments.
  
  
  CONCLUSIONS
  Data emerging from studies in human and experimental models of autoimmunity suggest that IL-21 is critically involved in the initiation and/or progression of inflammatory reactions where self-reactive immune cells or antibodies cause damage in tissue. Thus, theoretically, targeting IL-21 could help attenuate the activation of inflammatory pathways and facilitate the resolution of tissue damaging immune responses. However, one should also take into consideration some potential risks that could derive from the blockade of IL-21.
authors.affiliation: Dipartimento di Medicina Interna, Università Tor Vergata, Via Montpellier, 1, 00133 Rome, Italy.
authors.forename: Massimiliano
authors.initials: M
authors.lastname: Sarra
authors.forename: Eleonora
authors.initials: E
authors.lastname: Franzè
authors.forename: Francesco
authors.initials: F
authors.lastname: Pallone
authors.forename: Giovanni
authors.initials: G
authors.lastname: Monteleone
mesh_terms: D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology*; D001402:B-Lymphocytes / Q000276:immunology; D016503:Drug Delivery Systems; D006801:Humans; D007154:Immune System Diseases / Q000188:drug therapy / Q000276:immunology; D007249:Inflammation / Q000188:drug therapy* / Q000503:physiopathology; D007378:Interleukins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D013601:T-Lymphocytes / Q000276:immunology; D000098546:Interleukin-21
chemical_list: D000893:Anti-Inflammatory Agents; D007378:Interleukins; D000098546:Interleukin-21